1. Field of the Invention
The present invention is directed to a method of supporting a roof, particularly a roof of an underground excavation such as a mine, and to a system for carrying out the method, i.e. to apparatus for this purpose.
2. The Prior Art
In underground excavations, for example in mining galleries, tunnels and the like, it is usually necessary to support the roof of the excavation against cave-in under the pressure of the overburden. Various approaches for effecting such support are known from the prior art. For example, in coal mining it is known to use the so-called "room and pillar system" in which roof bolting is used, i.e. steel rods or bars which penetrate the rock layers and hold them together to prevent collapse. It is also known to provide various types of supporting structures of wood and/or steel in which rigid or slightly yieldable supporting elements are used to support the roof from below against collapse.
The problem with this latter type of approach, to which the present invention is also directed, is that the prior-art proposals are all relatively complicated and expensive and are difficult to erect and to move. The elements involved are relatively expensive and of considerable weight so that they are difficult to handle. There is also a decided lack of economy, both in the materials involved and in the installation work required.